JP2803592B2 - Combined plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a plurality of gas turbines,
Ammonia injection installed in heat recovery boiler and its exhaust gas system
Involved in a combined plant composed of in-line denitration equipment
In particular, when starting the gas turbine, NO
The present invention relates to a combined plant for reducing x. [0002] 2. Description of the Related Art NOx reduction measures for combined plants
In gas turbines, steam injection, low NOx combustor
It is adopted, and the waste heat recovery boiler uses ammonia injection
NOx reduction using denitration equipment using dry catalytic reduction method
Is being planned. Related to this type of device are:
For example, there is JP-B-59-32645. [0003] SUMMARY OF THE INVENTION Generally, a combined
The plant is a system that combines multiple small-capacity units.
Configure columns. Therefore, NOx is NO as the entire series.
x, that is, the sum of NOx emitted for each unit is
It must be controlled to be below the regulation value. By the way, in a combined plant, a negative
Load change is performed by switching the number of gas turbines. Also,
Operating mode is mainly DSS (Daily start & stop) operation
It is a flow and the start and stop of the gas turbine are frequently performed. Recently, even when the gas turbine is started, NOx
Observing regulatory values has begun to be viewed as a problem. But Gusta
-When starting the bin, the NOx reduction measures
The starting NOx characteristics of the unit are as shown in FIG.
After a certain peak is generated, the characteristic becomes steady. This pic
As a measure to reduce the peak value, the gas turbine
Means for maintaining the rotation speed for a certain period of time have been proposed. Only
However, when starting such a unit, the gas having NOx characteristics
When starting the turbine, the startup case,
Depending on the combination of the number of transfer units and the number of additional activation units.
Therefore, the peak value of the total NOx emission value
In some cases, the regulation value may be exceeded. An object of the present invention is to provide a gas turbineofStart-upTime
In addition, the total NOx emission value from the series exceeds the regulation value
Combined plan to reduce NOxTo
To provide. [0007] SUMMARY OF THE INVENTION The present invention relates to a gas turbine.
When starting, if there is a unit that is running ahead,
PrecedingReset the NOx set value of the operating unit, and
Depending on the result, by controlling the ammonia injection amount
Keep the total NOx emission value from the system below the regulation value
It is characterized by that. [0008] A second feature of the present invention is that an additional starting gas is used.
The turbine is held at a rotation speed of about 40%, and the rotation speed is maintained.
Determine the holding time from the total NOx emission value emitted from the series
Control system. A third feature is that the gas turbine is additionally started.
From the total emission value of NOx emitted from the series
The point is to have a control system to decide. [0010] Further, a fourth feature is that the gas to be additionally activated is provided.
The holding time and starting time for holding the turbine at a rotation speed of about 40%
Both dynamic intervals are calculated from the total NOx emissions from the series.
The point is to have a control system to decide. [0011] [Operation] Operate the NOx emission of the gas turbine to be started
To reduce NOx emissions from gas turbines
Than,TotalEmissions can be taken as reference values. [0012] DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
You. The gas turbine 1 has a core for producing compressed air.
Compressor 2 and compressed air and fuel from this compressor
And low NOx combustor for producing combustion gas by mixing
Composed of a gas turbine 4 operated by combustion gas
The generator 5 and the steam turbine 7 are connected to the turbine shaft.
Have been. The combustion gas that has worked in the gas turbine 4 is exhausted.
Sent to the heat recovery boiler 6,
Steam for driving the steam turbine 7 is produced. The steam that has worked in the steam turbine 7 is condensed
The condensate is condensed by a boiler feed pump 9
It is sent into the waste heat recovery boiler 6 and exchanges heat with
I am worried. The generated steam is sent to the steam turbine 7 again.
Can be In the exhaust heat recovery boiler 6, a denitration device 1 is installed.
The denitration apparatus 10 is provided with an ammonia injection port.
The ammonia from the pump 11 is supplied to the ammonia flow control valve 12
Is injected through. This ammonia flow control valve 12
Open / close by command from unit NOx control device 13
You. The fuel is transmitted to the low NOx combustor 3 at a fuel flow rate.
Sent through the unit 14 and its signal is controlled by the unit NOx control.
It is sent to the device 13. The exhaust gas at the outlet of the exhaust heat recovery boiler 6
The contained NOx concentration is detected by the unit NOx concentration transmitter 15.
And the detection signal is sent to the unit NOx controller 13.
Sent. Further, the gas temperature at the inlet of the denitration device 10 is
Detected by the transmitter 16 and the detection signal is also output from the unit NOx
It is sent to the control device 13. The above is defined as one unit 17 and a plurality of units
Exhaust gas discharged from the knit is collected in the chimney 18 and
It is discharged from the chimney 18 as the exhaust gas of the runt. Each unit NOx control device 13 is a
Connected to the NOx control device 19 for controlling the NOx of the
ing. Referring to FIG. 2, unit NOx control device 1
3 will be described. The unit NOx control device 13
NOx setting sent from x control device 19value,as well as,
NOx concentration transmitter 1NOx concentration sent from 5Yo
The ammonia flow control valve 12 is opened and closed. In addition, advance luck
In the rotating unit, the amount of exhaust gas is
21 is calculated, and the unit scheduled to be started up additionally has a denitration device.
Start mode 22 (hot start
(Cold start / cold start). these
Is calculated and the NOx concentration transmitter 15 has the series NO.
It is sent to the x control device 19. Referring to FIG. 3, the system NOx control device 19
explain about. In the system NOx control device 19, an additional starting unit
Given the knit number 23, each unit NOx control device
Denitration efficiency or leak ammonia concentration
The lowest NOx set value 20 determined from the degree is sent. Destination
NOx concentration transmitter 15 and exhaust gas amount 2 of the line operation unit
The actual NOx value of the entire preceding operation unit is calculated from 1
You. From the difference between this value and the NOx regulation value,
The total exhaustable NOx value is calculated. This value and addition
Additional startup from the number of startup units 23 and each startup mode 22
Unit startup interval 24 or 40% rotation speed retention
The time 25 is calculated, the priority evaluation is performed, and the unit controller 2
6 (FIG. 1). The unit controller 26
The unit is activated based on this. When the activation of all units is completed, the series NO
The x control device 19 determines that the calculated actual NOx value is equal to or less than the regulation value.
Calculates the NOx set value 20 of each unit so that
Then, it sends it to the unit NOx control device 13. Next, the operation will be described. Here is the destination
When two additional operation units are started when there are four line operation units
An example will be described with reference to FIGS. First, a signal indicating that the number of additional activation units is two
When 23 is sent to the series NOx control device 19,
Denitration of the four middle unit NOx control devices 13
Efficiency or release from the waste heat recovery boiler 6 unreacted
Leaked NH_ThreeN determined by the value of
The Ox set value 20 is sent. In response, each unit N
The Ox control device 13 controls the ammonia flow control valve 12
This is the exhaust heat recovery boiler outlet NOx concentration transmitter 15.
Control. Thus, the preceding operation unit NO
x is reduced. In the system NOx control device 19, an additional
Calculate the schedule of the start unit, and
Starting time 24 or 40% rotation speed holding time 25
To the unit controller 26. This allows the unit
Is started. At the time when the startup of the second unit is completed, the NOx setting
The fixed value 20 is released from the lowest value, and NOx is reduced first.
All units, including the preceding operation unit,
Due to the deviation between the total NOx emission value and the regulation value
Is controlled. The above example is a single-shaft combined plant.
Example, but with multiple gas turbines and less
Multi-shaft combined plug consisting of several steam turbines
May be applied to the client. [0031] According to the present invention, when starting the gas turbine,
NOx total emission value from series is kept below regulation value
Can be

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a basic configuration diagram of a plant according to one embodiment of the present invention. FIG. 2 is a configuration diagram of a unit NOx control device of the present invention. FIG. 3 is a configuration diagram of a series NOx control device of the present invention. FIG. 4 is a characteristic diagram of NOx discharged from the series of the present invention. FIG. 5 is a graph showing NOx characteristics at the time of startup discharged from the unit. [Description of Signs] 1 ... Gas turbine, 6 ... Exhaust heat recovery boiler, 12 ... Ammonia flow control valve, 13 ... Unit NOx control device, 14
... Fuel flow transmitter, 15 ... NOx concentration transmitter, 16 ... Temperature transmitter, 17 ... Unit, 19 ... Series NOx control device.

Claims (1)

(57) [Claims] In a combined plant that has a plurality of gas turbines, a plurality of exhaust heat recovery boilers, and a steam turbine, and injects ammonia into an exhaust gas system of the gas turbine to reduce NOx, when a gas turbine is additionally started, the operation is performed during operation . reconfigure the NOx setpoint of the gas turbine, the result, combined plant and having a control device for controlling the injection amount of ammonia. 2. According to claim 1, wherein the control device, characterized in that the additional starting the gas turbine which was maintained at around 40% rotational speed is controlled by determining the rotational speed holding time from the NOx total emission limit value of the total gas turbine Combined plant. 3. According to claim 1, wherein the control device, combined plant and controls to determine the initiation interval of a gas turbine to add boot from the NOx total emission limit value of the total gas turbine. 4. According to claim 1, wherein the controller controls to determine both the retention time and the initiation interval of holding at a rotation speed of around 40% of the gas turbine to add activated from the NO x total emission limit value of the total gas turbine Combined plant characterized by that.